'\" te
.\" Copyright (c) 2009, Sun Microsystems, Inc.  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
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.TH TRAN_SETUP_PKT 9E "July 31, 2021"
.SH NAME
tran_setup_pkt, tran_teardown_pkt, tran_pkt_constructor, tran_pkt_destructor \-
SCSI HBA packet allocation and deallocation
.SH SYNOPSIS
.nf
#include <sys/scsi/scsi.h>

\fBint \fR\fBprefix_tran_setup_pkt\fR(\fBstruct scsi_pkt *\fR\fIpkt\fR,
     \fBint (*\fR\fIcallback\fR) (\fIcaddr_t\fR), \fBcaddr_t\fR \fIarg\fR);
.fi

.LP
.nf
\fBvoid\fR \fBprefix_tran_teardown_pkt\fR(\fBstruct scsi_pkt *\fR\fIpkt\fR);
.fi

.LP
.nf
\fBint\fR \fBprefix_tran_pkt_constructor\fR(\fBstruct scsi_pkt *\fR\fIpkt\fR,
     \fBscsi_hba_tran_t *\fR\fItranp\fR, \fBint\fR \fIkmflags\fR);
.fi

.LP
.nf
\fBvoid\fR \fBprefix_tran_pkt_destructor\fR(\fBstruct scsi_pkt *\fR\fIpkt\fR,
     \fBstruct scsi_hba_tran_t *\fR\fItranp\fR);
.fi

.SH INTERFACE LEVEL
illumos architecture specific (illumos DDI).
.SH PARAMETERS
.ne 2
.na
\fB\fIpkt\fR\fR
.ad
.RS 12n
Pointer to the \fBscsi_pkt\fR(9S) structure.
.RE

.sp
.ne 2
.na
\fB\fIflags\fR\fR
.ad
.RS 12n
Flags for associating DMA resources with the packet.
.RE

.sp
.ne 2
.na
\fB\fIcallback\fR\fR
.ad
.RS 12n
Pointer to either \fBNULL_FUNC\fR or \fBSLEEP_FUNC\fR.
.RE

.sp
.ne 2
.na
\fB\fIarg\fR\fR
.ad
.RS 12n
Always \fINULL\fR.
.RE

.sp
.ne 2
.na
\fB\fIkmflags\fR\fR
.ad
.RS 12n
Either \fBKM_SLEEP\fR or \fBKM_NOSLEEP\fR.
.RE

.SH DESCRIPTION
The \fBtran_setup_pkt()\fR and \fBtran_teardown_pkt()\fR vectors in the
\fBscsi_hba_tran\fR(9S) structure are alternatives to the \fBtran_init_pkt()\fR
and \fBtran_destroy_pkt()\fR entry points. They are initialized during the
\fBHBA\fR driver's \fBattach\fR(9E) and they are used when a target driver
calls \fBscsi_init_pkt\fR(9F) and \fBscsi_destroy_pkt\fR(9F).
.SS "tran_setup_pkt(\|)"
The \fBtran_setup_pkt()\fR vector is the entry point into the \fBHBA\fR which
is used to initialize \fBHBA\fR specific information in a \fBscsi_pkt\fR
structure on behalf of a SCSI target driver. All fields documented in
\fBscsi_pkt\fR(9S) are initialized.
.sp
.LP
If the \fBHBA\fR driver chose not to preallocate memory for \fBpkt_cdbp\fR
and/or \fBpkt_scbp\fR, it must allocate the requested memory at this time and
point \fBpkt_cdbp\fR and \fBpkt_scbp\fR to the allocated memory.
.sp
.LP
An \fBHBA\fR driver which provides a \fBtran_setup_pkt\fR entry point inspects
the \fBpkt_numcookies\fR and \fBpkt_cookies\fR fields at \fBtran_start\fR time
to set up the transfer. If \fBpkt_numcookies\fR is zero, there are no \fBDMA\fR
resources associated with this packet. If \fBpkt_numcookies\fR is not zero, it
indicates the number of \fBDMA\fR cookies that \fBpkt_cookies\fR points to.
.sp
.LP
The \fBpkt_tgtlen\fR field contains the length of the packet private area
pointed to by \fBpkt_private\fR, allocated on behalf of the SCSI target driver.
.sp
.LP
The \fBpkt_scblen\fR field contains the length of the SCSI status completion
block pointed to by \fBpkt_scbp\fR. If the status length is greater than or
equal to sizeof (\fBstruct\fR \fBscsi_arq_status\fR) and the
\fBauto-rqsense\fR capability has been set, automatic request sense (\fBARS\fR)
is enabled for this packet. If the status length is less than \fBsizeof\fR
(\fBstruct\fR \fBscsi_arq_status\fR), automatic request sense should be
disabled for this pkt if the \fBHBA\fR driver is capable of disabling \fBARQ\fR
on a per-packet basis.
.sp
.LP
The \fBpkt_cdblen\fR field contains the length of the SCSI command descriptor
block.
.sp
.LP
The \fIcallback\fR argument indicates what the allocator routines should do
when resources are not available:
.sp
.ne 2
.na
\fB\fBNULL_FUNC\fR\fR
.ad
.RS 14n
Do not wait for resources. Return \fB-1\fR when resources are not available.
.RE

.sp
.ne 2
.na
\fB\fBSLEEP_FUNC\fR\fR
.ad
.RS 14n
Wait indefinitely for resources.
.RE

.SS "tran_teardown_pkt(\|)"
The \fBtran_teardown_pkt()\fR is the entry point into the \fBHBA\fR that must
free all of the resources that were allocated to the \fBscsi_pkt\fR(9S)
structure during \fBtran_setup_pkt()\fR.
.SS "tran_pkt_constructor(\|) tran_pkt_destructor(\|)"
When using \fBtran_pkt_setup()\fR and \fBtran_pkt_teardown()\fR,
\fBtran_pkt_constructor()\fR and \fBtran_pkt_destructor()\fR are additional
optional entry points that perform the actions of a constructor and destructor.
The constructor is called after the following fields in the \fBscsi_pkt\fR
structure have been initialized:
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_address\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_ha_private\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_cdbp\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_private\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_scbp\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_cdblen\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_tgtlen\fR
.RE
.RS +4
.TP
.ie t \(bu
.el o
\fBpkt_scblen\fR
.RE
.sp
.LP
Allocating and freeing a \fBDMA\fR handle are examples of something that could
be done in the constructor and destructor. See \fBkmem_cache_create\fR(9F) for
additional restrictions on what actions can be performed in a constructor and
destructor.
.sp
.LP
HBA drivers that implement \fBtran_setup_pkt()\fR must signal
\fBscsi_pkt\fR(9S) completion by calling \fBscsi_hba_pkt_comp\fR(9F). Direct
use of  the \fBscsi_pkt\fR \fIpkt_comp\fR field is not permitted and results in
undefined behavior.
.SH RETURN VALUES
\fBtran_setup_pkt()\fR must return zero on success, and \fB-1\fR on failure.
.SH SEE ALSO
.BR attach (9E),
.BR tran_sync_pkt (9E),
.BR bioerror (9F),
.BR ddi_dma_buf_bind_handle (9F),
.BR kmem_cache_create (9F),
.BR scsi_alloc_consistent_buf (9F),
.BR scsi_destroy_pkt (9F),
.BR scsi_hba_attach (9F),
.BR scsi_hba_pkt_alloc (9F),
.BR scsi_hba_pkt_comp (9F),
.BR scsi_hba_pkt_free (9F),
.BR scsi_init_pkt (9F),
.BR buf (9S),
.BR scsi_address (9S),
.BR scsi_hba_tran (9S),
.BR scsi_pkt (9S)
.sp
.LP
\fIWriting Device Drivers\fR
